The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Residual gas is the burned air/fuel mixture that remains in a cylinder after a combustion event in a spark-ignited gasoline internal combustion engine. The amount of residual gas has a significant effect on emissions, performance, combustion stability, and volumetric efficiency.
Residual gas affects the combustion process in spark-ignition engines through its influence on charge mass, dilution, temperature and flame speed. These effects may be important for optimizing engine idle stability, fuel economy and NOx emission. Current residual gas estimation strategies are inaccurate and unable to adjust for different altitudes.